Echo a maktaba-formatted error if clang-format output is unparseable.

This is needed in order to effectively unit-test against the situation
in which clang-format produces no output. In this case, there is a JSON
parsing error (since there isn't any JSON to parse). By using a
formatted error here, vroom is able to bail out when the error is not
handled properly.

Signed-off-by: Wolfgang E. Sanyer <WolfgangSanyer@Google.com>

Author: ezzieyguywuf

autoload/codefmt/clangformat.vim

@@ -182,8 +182,8 @@ function! codefmt#clangformat#GetFormatter() abort
         let [l:new_line, l:new_col] = s:OffsetToPosition(l:offset, l:formatted)
         call cursor(l:new_line, l:new_col)
       catch
-        call maktaba#error#Warn('Unable to parse clang-format cursor pos: %s',
-            \ v:exception)
+        call maktaba#error#Warn(v:exception)
+        call maktaba#error#Warn("  Unable to parse clang-formon cursor position")
       endtry
     else
       call maktaba#buffer#Overwrite(1, line('$'), l:formatted)